An international team of astronomers led by the University of Amsterdam (The Netherlands) suspects that neutron stars with a strong magnetic field can still launch so-called jets. Since the 1980s, it was thought that strong magnetic fields inhibit the formation of these plasma streams. But observations with more advanced telescopes indicate jet-like radiation. The astronomers publish their findings in two articles in the Monthly Notices of the Royal Astronomical Society.

Jets are energy rich plasma streams that are blown out of black holes or neutron stars at high speed. Jets have been known for decades, but so far no jets have been observed at neutron stars with a strong magnetic field. The prevailing assumption was that strong magnetic fields prevent the formation of jets. Since the eighties, astronomers hardly actively looked for jets at neutron stars with a strong magnetic field.

Artist's impression of the launching of a jet by a neutron star. Gas, stripped from the normal star in the background, first spirals towards the neutron star before being expelled in a powerful stream of plasma.

This movie from NASA's Chandra X-ray Observatory shows a fast moving jet of particles produced by a rapidly rotating neutron star, and may provide new insight into the nature of some of the densest matter in the universe. The star of this movie is the Vela pulsar, a neutron star that was formed when a massive star collapsed. The Vela pulsar is about 1,000 light years from Earth, spansis about 12 miles in diameter, and makes over 11 complete rotations every second, faster than a helicopter rotor. As the pulsar whips around, it spews out a jet of charged particles that race out along the pulsarâs rotation axis at about 70% of the speed of light.